BAEL-803: Backward Chaining with Drools - parent module (#2986)

* spring beans DI examples

* fix-1: shortening examples

* List of Rules Engines in Java

* BAEL-812: Openl-Tablets example added

* BAEL-812: artifacts names changed

* BAEL-812: moving rule-engines examples to rule-engines folder

* BAEL-812: removing evaluation article files

* BAEL-812: folder renamed

* BAEL-812: folder renamed

* BAEL-812: pom.xml - parent added

* BAEL-1027: Introduction to GraphQL - initial commit

* BAEL-781: Explore the new Spring Cloud Gateway

* BAEL-781: Fix UserService.java

* BAEL-781: Fix user-service pom.xml

* BAEL-781: remove eureka-server from the example

* BAEL-781: modifying example

* BAEL-803: Backward Chaining wih Drools

* BAEL-803: pom.xml

* BAEL-803: Backward Chaining with Drools - new example

* BAEL-803: Backward Chaining with Drools - parent module

* BAEL-803: Backward Chaining with Drools - parent module

* BAEL-803: Backward Chaining with Drools - meta-inf/maven-fix

* BAEL-803: Backward Chaining with Drools - drools parent module

drools/backward-chaining/pom.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-
 	<modelVersion>4.0.0</modelVersion>
 
 	<artifactId>drools-backward-chaining</artifactId>
@@ -17,7 +16,6 @@
 	<properties>
 		<runtime.version>6.4.0.Final</runtime.version>
 	</properties>
-
 	<dependencies>
 		<dependency>
 			<groupId>org.kie</groupId>
@@ -26,7 +24,6 @@
 		</dependency>
 		<dependency>
 			<groupId>org.drools</groupId>
-			<artifactId>drools-core</artifactId>
 			<version>${runtime.version}</version>
 		</dependency>
 		<dependency>
@@ -35,4 +32,4 @@
 			<version>${runtime.version}</version>
 		</dependency>
 	</dependencies>
-</project>
+</project>

drools/backward-chaining/src/main/java/com/baeldung/drools/BackwardChaining.java

@@ -21,13 +21,11 @@ public class BackwardChaining {
         KieSession ksession = kContainer.newKieSession("ksession-backward-chaining");
         ksession.setGlobal("result", result);
         ksession.insert(new Fact("Asia", "Planet Earth"));
-//        ksession.insert(new Fact("China", "Asia"));
+        // ksession.insert(new Fact("China", "Asia"));
         ksession.insert(new Fact("Great Wall of China", "China"));
 
         ksession.fireAllRules();
 
         return result;
-
     }
-
 }

drools/backward-chaining/src/main/resources/com/baeldung/drools/backward_chaining/rules.drl

@@ -0,0 +1,27 @@
+package com.baeldung
+
+import com.baeldung.drools.model.Fact;
+
+global com.baeldung.drools.model.Result result;
+
+dialect  "mvel"
+
+query belongsTo(String x, String y)
+  Fact(x, y;)
+  or
+  (Fact(z, y;) and belongsTo(x, z;))
+end
+
+rule "Great Wall of China BELONGS TO Planet Earth"
+when
+    belongsTo("Great Wall of China", "Planet Earth";)
+then
+	result.setValue("Decision one taken: Great Wall of China BELONGS TO Planet Earth");
+end
+
+rule "print all facts"
+when
+    belongsTo(element, place;)
+then
+    result.addFact(element + " IS ELEMENT OF " + place);
+end

drools/pom.xml

@@ -7,6 +7,8 @@
     <groupId>com.baeldung</groupId>
     <artifactId>drools</artifactId>
     <version>1.0.0-SNAPSHOT</version>
+	
+	<packaging>pom</packaging>
 
     <parent>
         <groupId>com.baeldung</groupId>